Lifting-jack.



Patented June 1, 1909. a xsrmrrrs-smerm- 1.

mvsu-ron 4 M. L. JENKINS.

LIFTING JACK APPLICATION FILED OUT. 1, 1908.

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LIFTING APPLIUATIO Patented June 1,1909.

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LIFTING JACK.

APPLIUATION FILED OUT. 1, 1908.

923,657. Patented Ju 1909.

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wiuimu WCATES PATENT OFFICE.

MERRILL L. JENKINS, OF HARVEY, ILLINOIS, ASSIGNOR TO BUDA FOUNDRY &MANUFAC- TURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

LIF'IING-JACK.

Specification of Letters Patent.

Application filed October 1, 1908.

Patented June 1, 1909.

Serial No. 455,673.

To all whom it may concern:

Be it known that I, MERRILL L. JENKINS, a citizen of the United States,residing at Harvey, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Lifting-Jacks, of whichthe following is a specification.

The invention relates to jacks and particularly to those of the screwtype. The invention has for its primary objects; the provision of animproved form of anti-friction support for the cap; and the provision ofan improved arrangement for mounting the bearing plates employed anddistributing the wear on such bearing plates to the end that an increasein durability and ease of operation be secured. Certain embodiments ofthe invention are illustrated in the accompanying drawings, wherein:

Figure 1 is a longitudinal section through the jack,

Figure 2 is a plan view of the ball retainer employed,

{figure 3 is a side elevation of the retainer, an

Figures 4 and 5 are modified forms of retainers which may be employed.

Referring first to the general arrangement as shown in Figure 1, theprincipal parts may be enumerated as follows, 1 is the base or frame ofthe jack, 2 is the operating nut for the spindle, 3 is the liftingspindle threaded through the nut 2, 4 is the lifting member mounted forreciprocation upon the frame 1 and provided with a foot 5 and a cap 6,which cap is screw threaded into the top of the lifting member asillustrated, 7 is a bearing plate secured to the lower face of the cap,8 is the operating gear mounted upon the upper portion of the spindle 3,9 is a bearing plate mounted upon the upper face of the gear 8 andsecured so as to turn therewith, 10 are balls interposed between thebearing plates 7 and 9, 11 is a retainer for the balls (shown in detailin Figures 2 and 3), 12 is an operating pinion carried by the shaft 13,which shaft is journaled in a member 14 carried by the lifting member 4,and 15 is the holding pawl.

It will be noted that the gear 8 has a projecting hub portion 16 uponwhich the bearing plate 9 and retainer 11 are centered, and that theupper bearing plate 7 is centered about the upper end of the spindle 3.By this arrangement the spindle 3 constitutes in effect the centeringmember of both the hearing plates and retainer, and as a result theseparts are securely maintained in their proper relative positions. Itwill also be noted that the bearing may be very conveniently and easilyexposed by merely unscrewing the cap 5 and removing it with its attachedbearing plate 7. The cap is prevented from accidental unscrewing bymeans of the set screw 17. A hole 18 is provided through the cap for theapplication of a lubricant. It will be seen that the spindle is securelyguided both beneath the nut 2 in the frame 1, and above such nut at theextreme upper end of the spindle where such spindle engages the bearingplate 7 In order to properly distribute the load over the bearingplates, the retainer illustrated in enlarged detail in Figs. 2 and 3 ispreferably employed. This retainer is centered about the projectingportion of the hub 16 of the gear 8, and as illustrated is provided withthree 'rows of ball holes. Each of these rows of holes is divided intotwo sets of holes lying on the center lines 19 and 20, 21 and 22, and 23and 24. It will be noted that these center lines for each row of holesare offset from each other only a slight distance, the purpose being tomake the balls of each row run in two separate courses spaced only aslight distance from each other. The object achieved is a distributionof the wear over a larger area thereby increasing the durability of thebearing plate. If desired the rows might be provided with a greaternumber of center lines than two, thus still further distributing thewear. This construction greatly increases the life of the bearingwithout increasing the cost thereof or materially increasing the spaceoccupied by the hearing, as it will be seen that the row of balls havingthe two courses occupies only a slightly greater amount of space thanwould a single row of balls in exact circular alinement. This bearingconstruction is also especially advantageous in a jack as the loadscarried are very great and the tendency where balls are used is to weargrooves in the bearing plate in a short time. The arrangen'ientillustrated in Figures 2 and 3 practically doubles the area upon whlchthe weight is borne, and the groovlng of the plates is materiallylessened.

Figures 4 and 5 illustrate modified forms of retainers, Figure 4 showinga retalner with two rows of holes each of which rows is divided into twosets, while Figure 5 illustrates a retainer having a single row of holesdivided into two sets and adapted to run in two courses. These modifiedarrangements are suitable where smaller sizes of jacks are constructed.Various other arrangements may be substituted to meet requirements.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent is the following 1. Incombination in a jack, a frame provided with a nut, a spindle threadedthrough the nut, a lifting member mounted for reciprocation upon theframe and having a cap provided upon its under side with a bearingsurface, a gear secured to the spindle and having a projecting hubportion, a bear ing plate fitting around the hub portion, an annularball retainer having flanges at its inner and outer peripheries with aninterposed perforated plate for engaging the balls, the inner flange ofthe retainer fitting around the said hub portion, balls interposedbetween the bearing surface and the bearing plate, and means carried bythe lifting memher for rotating the gear.

2. In combination in a jack, a frame provided with a nut, a spindlethreaded through the nut, a lifting member mounted for reciprocationupon the frame and having a cap provided upon its under side with abearing surface, a gear secured to the spindle and having a projectinghub portion, a bear ing plate fitting around the hub portion, ballsinterposed between the bearing surface and the retainer but divided intoa plurality of sets of holes, the holes of each set being slightly outof circular alinement with the holes of each other set, and meanscarried by the lifting member for rotating the gear.

3. In combination in a jack, a frame provided with a nut, a spindlethreaded through the nut, a lifting member mounted for reciprocationupon the frame and having a cap provided on its under side with abearing surface, a gear secured to the spindle and carrying a bearingsurface upon its upper face in opposition to the other bearing sur face,balls interposed between the surfaces, a retainer for the balls providedwith a plurality of rows of holes concentrically arranged with respectto the center of the retainer, each of which rows is divided into aplurality of sets of holes, the holes of each set being in circularalinement, but slightly out of circular alinement with the holes of eachother set, and means carried by the lifting member for rotating thegear.

In testimony whereof I have hereunto signed my name in the presence ofthe two subscribed witnesses.

lvlEltRILL L. JENKINS. Witnesses GEO. E. STOWE, JNo. L. VALKER.

